Mold for airplane propellers



M. 0. ST. JOHN.

MOLD ro'a AIRPLANE PROPELLERS.

APPLICATION FIL ED FEB. 28, 1921.

Patented Apr. 4, 1922.

4 swans-sun 1 M. C. ST. JOHN.

MOLD FOR AIRPLANE PROPELLERS.

APPLICATION FILED m1. 221, 1921.

Patented Apr. 4, 1922.

4 SHEEIS-SHEET 2.

M. 0. ST. JOHN.

MOLD ma AIRPLANE PROPELLERS.

APPLICATION FILED FEB, 28,192!- Patented Apr. 4, 1922.

III

M. 0. ST. JOHN.

MOLD FOR AIRPLANE PROPELLERS.

APPUCATION FILED FEB. 28, 1921. I 1,41 1,310. Pate ted Apr. 4, 1922.

4 SHEEYSSHEET 4.

. 3 ms s 9% NW 1 Q. \N Q. 5m

UNITED STATES PATENT OFFICE.

MILES 0; ST. Jenn, or cnroaoo, ILLINOIS.

MOLD FOB ,AIRPL-ANE PROPELLERS.

ncauon'nled rebru r 2a, 1921. Serial No. 448,462.

To all whom my concern; 7 i

Be it known that I, M nes C. ST. JOHN, a

citizen of the United States, and a resident of the cityof Chicago,inthe county of Cook and State ofIllinois', have invented certain new anduseful Improvements in a Mold for Airplane Propellers; and I do hereby(1e,- clare that the following is a full, clear, and exact descri tionof the same, reference being had to t e accompanying drawings, and tothe numerals of reference marked thereon,

which-form a part of this specification.

This invention relates to molds for the vulcanizing of propeller bladesor of complete propellersfor use in connection with airlanes. I a

t is an object of this invention to provide a mold in which the heat forvulcanizing may be readily applied to all partsof the propel-' lei?blade which is to be vulcanized.

It is aiurther object of this invention .to provide a core which may beheated so that the interior surface of the molded object may bevulcanized also.

It is a further object of this invention to provide a mold in whicha'propeller blade i with a .core made ofa material other than Fig'iirerubber may be vulcanized with the .core in place. 7 V c z I It is afurtherobject oflthis invention to provide, a mold fora completepropeller in which the several parts may be heated and in which the moldis readily taken apart for the removal of the vulcanized objects whenthe operation is complete. v i

It is a further object of this invention to design a mold so that theflow of heat to the propeller being vulcanized shall be as nearly aspossible uni-forms'o that the resulting propeller shall be as nearly aspossible of uniform characteristics. Other and further important objectsof this invention will be apparent from the disclosures in thespecification and the accompanying drawings. v a

The invention (in a preferred form) is shown in the drawings andhereinafter more fully described. 7 a

On the drawings: Figure ,1 is a front view ofone form of mold involvingmy invention;

. Figure-2 is a plan ofthe same. Figure 3 is an end elevation, I Figure,4 is anend view of the'outei'most end parts removed. f

5 is a longitudinal verticalseetion.

'Figure-G is a view from the same end as Figure 4, with the parts shownin the middle of Figure 4 removed.

Figure 7 isa view of the same end of the propeller mold with the partsshown in F igure6 removed. I

Figure 8 is a horizontal longitudinal sec tion. I

Figure 9 is a longitudinalvertical sectional view showing amodification. g Figure 10 is an end view'of the inner face of the endpiece of the mold shown in Fig: ure 9.

Figure 11 is. an end view of the part abutting FigurelO.v Figure 12 isan edge view of a moldxfor making a complete propeller. Figure 13 is ahorizontal longitudinalsection of Figure 12, with the propeller inplace.

Figure-141 is aplan view of the lowermost a View ofa modified form ofre-18 i a vertical longitudinal of the mold and propeller shown inFigure 17. 1. v Figure 19 is a horizontal section of the central part ofFigure 18. a p Figure 20 isa section upon the line-20-20 of Figure19. [pv Figure 21 is a detail of certain parts shown in section in Figure 18.

Asshown onthe drawings: j The mold for a single blade is made up of therecessed plates 1, and 2 which: are surrounded by the steam jackets 3and 1. These steam jackets have. inlets 5 and outlets 6. It is theobject of this portion ofthe mold to form the outer surface of the bladeproper. The outer surface of the neck and of the flange separating neckand blade are formed by two parts '7 and 8.. The, part 7 has a chamber 9and the part 8 has a chamber 10. Steam is admitted to these chambersthrough the p'ipes 11 and. ledfrom them through the pipes 12. Themainplates of the parts? and 8 abut a-gain'stthe end plates ets 3 aneandarecovei'ed byithe plates 74 and 7 5. Upon the same sideof theplates 7 and S as the steam jackets and 1..-

are shoulders as shownin Figure 7, at T2 and 73 to make the flangeseparating the hub from the blade. Outside of theplates 7 and Sisanother-plate 13 containing 'the ,cl'iamberm; This chamber is closed" bya cover plate 17, having an inlet l and an outlet 16.-

In the midst of this cover plateis a hole 18 communicating with apassage 19 through the plate 13 leading'into theinterior 20 of a pieceof metal 21 which constitutes the core forming a part of the mold forthe propeller part 8 brought into contact with 4. The appropriatelyshaped piece of soft rubber 25 about to bevulcanized, with the core.21inserted in it, is then laid upon the specially formed'recess 26 of thepart 2. That part of the soft rubber bodywhieh is to form the lower halfof the fiange 27 between" the blade and the hub is introduced into therecess 73. The plate 1 is then placed'on top of 2, its recesscontacting" with the other-surface of the soft rubber which is to becomethe blade. 7 Next the part 7 is .put in place;

its recess 72 accommodating the other half of the flange 27 The plates74, 7 5 and 13 j are then added and thecover plate 17 put on.

The whole is then securely fastened to- 'gether by bolts 23. Steam isthen passed in "through the inlets 5 and ou t-"of th e out lets 6, alsothrough the chambers 9; 10 and 1-: by their several inlets and outlets,until the whole mold is heated sufli'ciently'to vulcanize the rubberbody. Steam may bcintroduced through the "opening 19 into theinterior-"20 of the core 21 The steam in the chambers 9 and 10 not onlyvulcanizes the hubpart of. the body but assists in heating the core.

When the-vulcanizing is over. the mold is.

"' taken apart, theblade 25 lifted out and the core 21" removedtherefrom. The blade is then ready for use and it may then be sembled.with other blades to form a pro peller, 1' i I j j modification is shownin Figure e to 11 infwhich the core 20* is shown solid instead ofhollow. No steamiis therefore in.- troduced into the. interior of thiscore. The

I, cover-plate 17 consequently is madewithout a centralhole; but it hasa steam inlet 15 and an outlet 16. Q The cham'berfl l; in the.

plate 13 is not changed but the cover plate 17 is ma'de enough higher sothat it does not,

contact with-the boss at the center of the ehamber '14 containing thepassage 19.'

' The modificationshown in Figures 12iand 13 is' for 'thejtnirp'ose' ofvulcanizing a com plete propeller instead of a single blade.

,The propeller is to have a core that remains in it. The mold for thepropeller includes an-upper part 30 and a lower part 31. VVithin these aspecially formed cavity 'to hold (3116,131'01361161 is provided.

plurality ofchambers in which there are inlets 33 and outlets 3 1 forsteam. A similar steam jacket is not shownabove 3O in ord'er toillustrate that -the 'mold'maybeused with or without the steam "jackets.fWhenitis used 'w'ithout'a steam jacket th'ejvliol e niold 7 Below; thepart 7 Ellis illustrated a steam jacket 32 havinga I isinserted inanoven for'vulcanizi'ngI VVhen it'is-used withi steam'j ackets it isthefintenQ We that ei hould. be one abovQ' Q .well as below 31. 1

'The mold is intended for propellersiwhicl'i are to permanently containa wooden or a m'etalQcore. "The core ofwood" is of the form shown indotted n s at in Figures sl'fii seals.

If the propeller is to havea hub that proj ects, the wooden coremayinclude the parts shown in full lines at 37 and 38; if not," fillerpieces are inserted at 37 "and 38'so} that the same moldcan be used forother forms. I These filler pieces are provided with holes through oneor more of which'pins maybe inserted which go through the holes in thewooden core provided for bolting the propeller to 'its'shaft." Thesepins serve to po-' sition. the core 'accurately within the mold and'tosupport it withinthe til the same is. vulcanized.

soft rubber un c The "metal core 35? shown: in Figure a luibsho'rterthan the width 'ofthe mold.

The pieces 37 and. 38 are therefore shown there .as filler pieces. "Whenthe hub xtend to thesurface of the moldthese are notnec essary. Whenused they are supplied with holes to align with the holesin the hubja'sin core it isalso desirable to add steame511; nections for heatingthelinterior of the body of rubbcr. asareindicated in. .16.

hen an entire propeller isjto' be molded at once andthere is to remainnocore with in the hollow'finished propeller-theformi of mold shown inFigi'ires 17; to 21 is used. Here there are the usual recessedplate's-41 an d heated by the steam j ackets' 43 an d fi l each containingseveral chambers with inlets 45. and outlets 41-6. The whole is nectedby tieplates 417 and bolts 48 j The body49 of soft ru'bber fhas withifit a cavity occupied bythe vulcanizing menihere 50, each of which ,i'shollowand is fed from a chamber in the part 54 havingan in let 51 andvan outletf52,j which are most clearly shown in'Eig'ure- 1 9 *This'figure does n how t e Wh eape io'n Qf't soft rubberfbo'dyis shownthef'outlinefif which corresponds totheoutlinelof' body at the centralpart ofth 'inold;""

The core to form the hollow part of the hub of the propeller has itsoutline formed by four pieces, two pieces 53 co -operating with twopieces 54, and includes other pieces for holding these in place. Thepieces 54 are hollow and communicate with the hollow vulcanizing membersand are fed as already explained by inlets 51 and outlets 52. The fillerblocks 53 are hollow and are fedby inlet and outlet connections and 56.The members 50 and 54 are secured together by hollow threaded pipecouplings 57. The inlet and outlet pipes 51, 52, 55 and 56 pass upthrough grooves in the central filler block 58 and connect with passagesnot.

shown in the plate 41. These grooves are suflicient to permit motion ofthe part 58 along the pipes without binding.

Below the members 53 the part 58 is of suflicient diameter to extend allthe way to the rubber body 49. Above the members 53 the part 58 is onlyof suificient diameter to extend to the innermost surface of the partssand 54. .The remainder of the space between the upperpart of themembe-r 58 and,

the rubber 49 is filled by an annular filler block 59.

The operation of this form of the device will be well understood from adescription of how the finished vulcanized propeller is removed from themold., W hen the vulcanization is completed the parts are in therelation indicated by Figures 18 and 19. To remove the propellerfrom themold the parts 44 and 41 are first lifted ofl. The pro peller is thenlifted out of the part 42 and.

the parts 50 to 59 come with it. The member 58 may then be removed fromthe propeller. If, as frequently is the case, this member sticks it canbe started by striking its smaller end with a hammer. The re moval'o'fmember 58 enables the workman to get at the inner edge of the annularmember 59 and it may be removed by inserting a tool between it and theupper inside edge of either of the members 53 or 54. The member 54 maythen be drawn toward the center conveniently removed.

53 are then readily accessible and may be The members 50 have then amplespace within which they may be moved to remove first one and then theother. With this explanation the operation of assembling the mold willbe obvious since the operations are only performed in the oppositeorder, first inserting the members 50, then securing the members 54thereto and inserting the members 53 in place, after which the member 59is placed and the member 58 driven home. The whole is then placed withinthe mold.

pipe connection between the two.

2. A mold for a vulcanized rubber pro- )eller com arisin a circularfiller block for the hub of said propeller, hollow core members for theinterior of the blade, hollow filler blocks between said circular memberand said hollow core members, inlet and outlet connections for leading aheating fluid into the interior of said filler blocks and cores. 7

3. In a mold for a propeller blade two core members, two connectingmembers at the neighboring ends of said core members, arcuate fillerblocks on each side of said connecting members, a circular filler block0011- centric with said arcuate members and extending above them, and anannular filler block above and concentric withsaid circular fillerblock.

4. A means forjsupporting a core within the interior of a mold for avulcanized rub ber propeller consisting oitwo filler blocks having holesin alinement with the. holes throughthe hub of the propeller, and a pin7 through said alined holes.

In testimony whereof I have hereunto subscribed my name in the presenceof two subscribing witnesses.

MILES C. ST. JOHN. Witnesses CARLTON HILL, JAMES ML OBRIEN.

